Zeng was found murdered at about 4:30 a.m. Sunday at a home in the 2100 block of Quesada Avenue. Four teens have been arrested in the case, including a 15-year-old boy on suspicion of murder.

Zeng was a San Francisco resident but did not live at the home where he was found, police said.

He was a sophomore at nearby Thurgood Marshall Academic High School, San Francisco Unified School District spokeswoman Heidi Anderson said.

Zeng’s death was initially reported as a possible suicide, but the medical examiner’s office quickly determined the death was suspicious, and the teens were arrested shortly afterward.

The 15-year-old boy who was arrested on suspicion of murder and the three other suspects – boys ages 15 and 17, and an 18-year-old man – all face attempted arson and conspiracy charges, police Lt. Troy Dangerfield said.

The attempted arson counts were added because police found an accelerant – either gasoline or kerosene – near where Zeng’s body was found, Dangerfield said.

A fifth suspect, also a teenage boy, is still at large, Dangerfield said.

The suspects’ names have not yet been released.

An autopsy was performed on Zeng on Monday, but his official cause of death has still not yet been determined, according to the medical examiner’s office.

The school district is making grief counseling services available at Thurgood Marshall this week for students affected by Zeng’s death, Anderson said.

A Facebook memorial page was set up in honor of Zeng by one of his friends.

In the description of the memorial page, its creator said, “Andy may you rest in peace and watch over the TMAHS family.”